Good evening. We begin with the president, sending off heated questions tonight about the death of the u.S. Ambassador chris stevens and three other americans who served in libya. Both the president and the secretary of state, hillary clinton, were pressed to answer whether this could have and 140u8d have been prevented. And abc's jon karl starts us off tonight. Reporter: It was the very first question for president obama at a univision forum in miami today. Why wasn't there more security at the u.S. Consulate in libya? He didn't directly answer. When the initial events happened in cairo and all across the region, we worked with secretary clinton to redouble our security. Our goal now is not only to make sure our embassies and our dip lope malts are safe, but also to make sure we bring those who coried out these events to justice. Reporter: The white house today for the first time called the assault a terrorist attack. But there are mounting questions about how it all happened. Was there actionable intelligence prior to this attack? And if there was not, why not? Reporter: The administration suggested there was no advance warning because the attack was a spontaneous reaction to the anti-muslim video that sparked protests in egypt last week. This was a spontaneous, not a premeditated response to what happened. Reporter: Republicans say th that is not right. It was not as a result of a youtube video. It was an orchestrated terrorist attack. It spokes the level, the abysmal level of their knowledge about fundamental aspects of terrorist attacks and militant operations. Reporter: A top intelligence official told congress yesterday that al qaeda likely did play a role, regardless of whether it was a pre-planned or spontaneous attack. Still developing facts and still looking for any indications of substantial advance planning. We just haven't seen that at this point. Reporter: Meanwhile, in tripoli today at a memorial for the four americans killed, libya's president paid tribute to ambassador chris stevens as a friend of the libyan people. There were reports today that stevens believed he was on a terrorist hit list. But secretary clinton and other u.S. Officials said today they have absolutely no reason to believe that that is true. Diane? Thank you so much, jon.

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